Manula is an undisputable first-choice goalkeeper for the Msimbazi Street-based side but recent rumours around his future have generated a lot of questions on whether he can accept an offer from Simba's CAF Champions League Group A rivals.
The reports have indicated Al Merreikh are ready to acquire the shot stopper, who is as well turning out for Tanzania's national squad 'Taifa Stars'.
Al Merreikh have tabled $8,000 as the sign-on fee but the goalkeeper has said he will not make a decision on the matter.
"The club knows about what might happen next but for me I know I have got a contract with Simba and it is them that will decide to sell me or not," he noted.
"As a player, I have to wait and hear what the club will say because they are the employers. If my contract was about to end, I would have made a decision but because it has not, it means the club will give way forward," Manula said.
He added: "They will decide whether the offer is good for them or not and they will also make a decision whether I will remain with them or not. I am here to work for Simba and ensure we achieve our targets. I am also here to make sure I achieve my individual set targets."
Manula also explained why they have been able to keep four clean sheets in the Champions League, even after playing tough matches like the one against Egypt's Al Ahly in Dar es Salaam.
"As a team, we always work as hard as possible to ensure we do not concede a lot of goals. With the unity and the coach's guidance I think we have generally done a good job," he stressed.
He added: "So far we have achieved four clean sheets in the Champions League group phase. We are preparing for our game with the hope that we are going to defeat AS Vita Club.''
''It is also my hope that we will keep a clean sheet so as to continue registering good records.
"My performance is improving day in and day out and this has been possible because I have been working hard and implementing what the coach wants me to. I cannot also forget to mention the team's effort generally as it has been quite good.''
"The team has been pushing hard and that is also making me, even more, better as a goalkeeper. I cannot also fail to mention the coach because whatever he is teaching seems to be good and that is why the performance is also top-notch," the three-time Vodacom Premier League's golden gloves winner noted.
Simba will face Democratic Republic of Congo (DRC)'s AS Vita Club tomorrow at home as the former look to seal a place in the last eight.
They remain unbeaten in Group A and will conclude the group matches against the 2019/20 CAF Champions League's winners, Al Ahly, whom they defeated 1-0 on match day three.
Simba have 10 points, three more than Al Ahly's tally while AS Vita are placed third with four points.
Al Merreikh are at the bottom having lost three games and posted draw in one